In my first job as android developer (circa 2010) I was tasked with porting a J2ME application with 30,000 lines of code in total to Android. Their primary condition was 'I shouldn't use any XML for layouts and any UI element should be defined only via code'.

I later understood that, it was because they wanted to use the J2ME-to-android bridge I develop for their other J2ME apps and XML layout dependencies would have been a hindrance. Since, this was very early in the android development ecosystem and many devs were Java developers before; usage of XML layouts for UI wasn't strictly mandated as it is now. I did complete the bridge in 3 months and the application performed as it should.

But, I'm glad I never had to do everything related to UI programatically on Android ever after.